MAGNETIC PHASE-TRANSITION IN AMORPHOUS FE73.5CU1NB3SI13.5B9 ALLOY

We have obtained the critical exponents, the corresponding amplitudes and the universal amplitude ratios for the amorphous Fe73.5Cu1Nb3Si13. 5B9 alloy from detailed bulk magnetization measurements performed in t he critical region near the magnetic phase transition temperature. The critical exponents determined are beta, gamma, gamma' and delta, amon g which beta describes the temperature dependence of the spontaneous m agnetization, gamma (T greater than or equal to T-C) and gamma' (T les s than or equal to T-C) describe the temperature dependence of the zer o-field susceptibility, and delta describes the field dependence of th e magnetization at the Curie temperature, T-C. The values of T-C obtai ned in the present investigation match very well those reported in the literature. The critical exponent values are very close to those theo retically predicted for the three-dimensional Heisenberg spin system.